Rating System

LEED ID+C: Commercial Interiors, LEED ID+C: Commercial Interiors

Rating System Version

v2 - LEED 2.0, v3 - LEED 2009

Inquiry

The project wishes to use Therma-Fusers in private offices to satisfy the intent of LEED CI Eac1.3. Therma-Fusers are supply air diffusers, which are each equipped with an individual thermostat, meaning they have "active controls capable of sensing space demand." However, although the Therma-Fusers do not specifically "modulate the HVAC system in response to space demand," they do satisfy the intent of the credit which is to "achieve increasing levels of energy conservation beyond the prerequisite standard to reduce environmental impacts associated with excessive energy use." Therma-Fusers function at low pressure, which can reduce the horsepower (and therefore reduce the energy demand) necessary to run the fan motor. This fan energy is further reduced because the VAV system serving this particular space incorporates variable speed drives, which allow the system to turn down even further to save more energy. Also, because a typical pressure independent VAV terminal unit can only turn down to 30%, Therma-Fusers save even more fan energy because they can turn down to less than 10% and maintain individual temperature control. Also, because each Therma-Fuser is a zone of control providing individual room control, heating and cooling energy are reduced because no portion of the building is ever over-cooled or over-heated. An independent study has shown 40% energy savings for interior zones and 29% energy savings for perimeter zones when individual room control was compared to multi-room control. Although Therma-Fusers may not save HVAC energy precisely in the manner specified by the credit, we believe, given the energy saving capabilities of incorporating Therma-Fusers within the space mentioned above, their use satisfies the intent of LEED CI EA credit 1.3.